Pairing in nuclear systems: from neutron stars to finite nuclei

We discuss several pairing-related phenomena in nuclear systems, ranging from superfluidity in neutron stars to the gradual breaking of pairs in finite nuclei. We focus on the links between many-body pairing as it evolves from the underlying nucleon-nucleon interaction and the eventual experimental and theoretical manifestations of superfluidity in infinite nuclear matter and of pairing in finite nuclei. We analyse the nature of pair correlations in nuclei and their potential impact on nuclear structure experiments. We also describe recent experimental evidence that points to a relation between pairing and phase transitions (or transformations) in finite nuclear systems. Finally, we discuss recent investigations of ground-state properties of random two-body interactions where pairing plays little role although the interactions yield interesting nuclear properties such as 0+ ground states in even-even nuclei.Comment: 74 pages, 33 figs, uses revtex4. Submitted to Reviews of Modern Physic

Determination of nanoporosity and free volume in a polymer blend system by means of positronium spectroscopy

[No abstract available

Invisible side of emotions: somato-motor responses to affective facial displays in alexithymia

According to recent theories, the detection of emotions involves somatic experiences. In this study, we investigated the relation between somatic responses to affective stimuli, emotion perception, and alexithymia. Variations in automatic rapid facial reactions (RFRs) were measured in a selected population of participants with high and low levels of alexithymia (HA and LA, respectively). Electromyographic activity was recorded from the corrugator supercilii and the zygomaticus major, while participants performed a gender classification task on faces expressing various emotional states. LA participants showed congruent RFRs in response to both fearful and happy stimuli. On the other hand, HA participants did not show congruent RFRs in response to fearful faces. They showed congruent, but delayed, RFRs in response to happy faces. These results provide evidence of a deficit in somato-motor emotional processing in people with high alexithymic personality traits, and thus support the hypothesis that alexithymia is associated with a deficit in emotional embodiment